The evaluation of some polyurethanes as maxillofacial prosthetic materials has been done. Four major results have been accomplished during this period. They are: a) the incorporation of a filler to optimize the properties of Epithane-3; b) the location of additional sources of polyurethanes; c) a detailed evaluation of IPDI type polyurethanes; and d) the screening of the potentiality of UV stabilizers and their effectiveness. In the process of optimizing properties, we found incorporation of a filler largely improved the material. The main difficulty is the requirement for making the mixture homogeneous. The identification of the members of the Polyurethane Manufacturers Association provides us a positive and direct source for locating additional candidate materials. The evaluation of IPDI type polyurethanes shows that these polyurethanes display properties very close to the standard criteria for a maxillofacial prosthetic material. The only problem involved in polyurethanes, in general, is their UV instability. Tackiness and yellowing are the two common phenomena resulting from UV aging. UV stabilizers have been employed but the results are not too promising due to both a lack of theoretical background and pertinent experimental data. Additional research should be initiated to overcome this obstacle. BIBLIOGRAPHIC REFERENCE: New and Improved Elastomers for Extraoral Maxillofacial Prostheses. D.H. Lewis, D.R. Cowsar, D.J. Castleberry, and T.E. Fischer. Southern Research Institute, Birmingham, Alabama 35205 and School of Dentistry, Birmingham, Alabama 35294. To be published in the International Association for Dental Research: Abstracts of 1977 Meeting, Copenhagen, Denmark. 1977, in press.